Felipe Massa says the final pre-season test will be crucial for Ferrari as it brings major upgrades to the car ahead of the first race in Australia.

Massa completed just one day in the car this week as team-mate Fernando Alonso returned to action over the first three days. He said there were no major changes from Jerez and that the true potential of the new F138 would only start to be realised at the final test next week.

"The car is exactly the same as we had in Jerez," he said. "As we finished Jerez, sure we found some little details around the car that maybe we changed again for here, but it is more of an evolution and not new pieces or anything.

"Now is the really important time when we bring new pieces to the car. The car is still green so we need to put the car in good shape ahead of the first race and there is a lot of work to do. It's a very important moment for the people working on the aerodynamics and the engine and the chassis and everything in order to prepare everything together in the right direction for the first race."

However, Massa is feeling more at ease with the car this year than he did at the start of 2012.

"I feel much more comfortable in the car and with the balance as well," he added. "I think what we did in Jerez was quite positive and all the changes we did on the car as well. The car was quite balanced and that's very important. Here it was not so much because we had a very difficult day with the conditions, but in the rain the car was quite good to drive and quite competitive as well through the run.

"I feel okay and good in the car but I haven't had long in the car. It's important to use the next week very well with the two days I have and the two days Fernando has to be fully ready for the first race."